Both are viral, but flu is more likely to bring on a fever, flu is also likely to be much more severe than a common cold and last longer! You know if have the flu if you have a fever, headache, and symtoms that persist 2-3 weeks!
Colds are much more mild than flu, and you can still function.
The irony is that a flu short does not protect you against a cold, only that years flu virus.
